Gene:
What is the intended purpose for the radials according to those who
recommended their installation? Lightning protection? Will they be deeply
buried or just lying on the surface of the ground? From your posting, I
conclude you otherwise had no intention of putting in a grounding system of
any kind. That's tempting fate, IMO.
I suggest you get a copy of Polyphaser's book The Grounds for
Lightning Protection. Great source of design info on protecting your tower,
coax and home wiring from lightning effects. The best illustration in the
book is a series of drawings depicting how a lightning strike "saturates"
the earth around your tower and ground conductors with its energy. The
objective of a ground system is to give the energy enough "earth" to dump
into harmlessly, like using sponges to mop up a liquid spill. If the sponge
isn't big enough (not enough wire in conductive earth), the sponge (earth)
will not be able to absorb the liquid (lightning energy.) Without
additional ground conductors, your planned tower and concrete base would be
like a small piece of sponge - unable to absorb and dissipate safely all the
energy contained in a strike.
Read the Polyphaser book and decide whether three radials (connected to
ground rods pounded into the earth, BTW) would be enough for your
installation.
GL es 73 de
Gene Smar AD3F
P.S. The design standard for towers, TIA/EIA 222, calls for two driven
ground rods connected to two tower legs at a minimum. Concrete base is not
enough of a ground, per the standard.
-----Original Message-----
From: Eugene Jensen <eugenejensen@nyc.rr.com>
To: towertalk@contesting.com <towertalk@contesting.com>
To: <towertalk@contesting.com>
Date: Saturday, July 21, 2001 1:34 AM
Subject: [TowerTalk] Radials attached to tower legs
>
>I am in the process of installing a U.S. Tower HDX 455 that will have a
>Force 12 Magnum 280B, 80 meter yagi installed. There will also be a 40
>meter yagi above that. There has been a recommendation that I run 3
quarter
>wave length copper ground radials from the tower. Does anyone have any
>experience with this other than obviously an improved electrical path for
>lightning? I have no plans for turning the tower into a vertical. Thanks.
>Gene. K2QWD
>
>
>List Sponsor: Are you thinking about installing a tower this summer? Call
us
>for information on our fabulous Trylon Titan self-supporting towers - up to
>96-feet for less than $2000! at 888-833-3104 <A
HREF="http://www.ChampionRadio.com";>
>www.ChampionRadio.com</A>
>
>-----
>FAQ on WWW: http://www.contesting.com/FAQ/towertalk
>Submissions: towertalk@contesting.com
>Administrative requests: towertalk-REQUEST@contesting.com
>Problems: owner-towertalk@contesting.com
>
List Sponsor: Are you thinking about installing a tower this summer? Call us
for information on our fabulous Trylon Titan self-supporting towers - up to
96-feet for less than $2000! at 888-833-3104 <A
HREF="http://www.ChampionRadio.com";>
www.ChampionRadio.com</A>
-----
FAQ on WWW: http://www.contesting.com/FAQ/towertalk
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
|